1. Field of the Invention
The present invention generally relates to database management systems. More particularly, the present invention relates to using a plurality of subscriber types in managing a message queue of a database management system.
2. Related Art
Typically, a database management system (DBMS) implements a messaging architecture for information sharing in the DBMS. The messaging architecture includes at least one message queue that functions as a repository for messages. A message may be any type of data. Publishers are entities that publish new messages to the message queue. Subscribers are entities that consume messages from the message queue. The DBMS creates subscribers to the message queue in response to requests from clients. The clients can be database users, software programs, etc. Usually, the subscriber is interested in messages that satisfy a set of rules of the subscriber. Moreover, the creation of subscribers generally requires the creation of specific access privileges to the message queue on a per-subscriber basis to maintain security.
Further, the DBMS may allow clients to set up individual event notification registrations to notify the clients when certain DBMS-related events occur. Examples of DBMS-related events include, for example, messages being published to a particular message queue that satisfy the set of rules of a particular subscriber, instances or databases going up or down, database objects changing, and system alerts being issued.
Each event notification registration includes DBMS-related event(s) of interest and the manner of delivering the event notification to the client. For example, delivery may be made over a network to a client specified host and port, may be made by email, may be made by HTTP, or may be made by invocating a stored PL/SQL procedure. To clients, some DBMS-related events of interest are more important than others.